1983 Chevy Camaro Rearend - Posi-tive Performance

We Opt Out Of Our 10-Bolt Contract In Our Third-Gen With A Beefy New 12-Bolt And Posi Rearend.

Moving forward with our Project Crossfire Z, an '83 Camaro, we are slowly but surely repairing or replacing most of the worn, abused, and neglected parts on the 140,000-mile beauty. In preparation for the arrival of our 400hp Dart SHP engine (complete details in an upcoming issue), and having our third-gen previously outfitted with a new Phoenix trans, it was time to finish updating our "beast's" drivetrain.

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Of course, the plans called for a positraction unit for the rearend with a full complement of stiffer gears, new axles, seals, and bearings. Oh, and let's not forget a cast cover with bearing supports to button up all the beef. But, after a couple of hours of filling up our Summit Racing shopping cart, and adding up all of the parts needed to get our factory 71/2-inch 10-bolt up to par (see side bar), we decided that stepping up to the Moser 12-bolt package we'd been eyeing would be money well spent. It was hard to vote against the durability and coolness of Chevy's tried-and-true 12-bolt.

Is it worth it?
In an attempt to keep the costs of our project down, we fully intended on a nice build of our stock 71/2-inch ring gear-equipped rearend. But in trying to keep it simple, we ran into a full plate of "as long as you have it apart, you might as well ..." to the tune of about $1,400. While considerably less than the Moser package, when all was said and done, we would still have a 71/2-inch ring gear-equipped rear end, albeit one that would probably handle our 400 hp forever. But what if someday we found 500 or 600 hp to drop in? It's just another thing to consider.

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1983 Chevy Camaro Rearend - Posi-tive Performance

Removing the old 10-bolt was pretty straightforward, especially if you have the luxury of a rack as we do in the Source Interlink Tech Center. Simply unbolting shocks, panhard bar, control arms, and springs will get the job done.

Here's our Moser 12-bolt assembly. It comes bolted together and almost ready to go. Every Moser 12-bolt begins life as a brand-new, cast nodular iron housing. We paid an extra $250 to have the assembly powdercoated black from the factory.

The rearend is a direct bolt-in for our third-gen F-body including spring perches mounted in the stock location and integrated control arm relocation brackets. The extra mounting holes in the relocation brackets allowed us to compensate for control arm down angle on our lowered car. We also ordered our rearend with large bearing, Ford-style ends to more easily allow for the adaption of the aftermarket Baer brakes that we intend to employ.

As do all Moser rearend assemblies, ours came with a set of their 30-spline forged steel axles that are put through an arduous manufacturing and testing process. For an extra $125, you can upgrade to 33-spline axles that are warranted for 10 years.

Our assembly came loaded with an Eaton Detroit Truetrac posi unit and Motive Gear 3.73 ring-and-pinion set. According to Moser, the Truetrac is the way to go as far as differentials. The unit uses helical gears instead of clutches, so they are considerably more durable.

The axle seals needed to be assembled in the housing before installing the axles. Make sure you do this with the spring side of the seal "in" using the proper seal installer. You don't want these things puking gear lube all over your new brakes.

In order to strengthen our rearend to the max, we opted to spend the extra $135 to upgrade to an extremely rigid, cast aluminum Moser Performance Rear Cover. The beefy lid's added support improves the ring-and-pinion's gear life, and gives your ride a down and dirty "all business" look from behind.

Here is one of the axles with studs loaded into the housing with the Baer intermediate bracket. We'll detail the brake install and performance testing in the next magazine issue.

After battling compatibility issues with competitor's suspension products, Moser decided to make things simple and began manufacturing their own chromoly control and torque arms.

The final piece of the suspension puzzle: Moser's adjustable torque arm.

To establish the initial length of the control arms, we matched the measurements of the stock arms.

Before hoisting the rearend assembly up into the car, we separated and attached the torque arm mount. We learned from our past mistakes that this is the easiest way to get the torque arm installed.

Since the Moser housing doesn't come with welded-on brackets, they include this clean clamp assembly. We used an Inline Tube kit and bent new steel brake lines.

A trip to Autozone helped us cook up this new brake line block that doubled, with the help of a 1/4-inch NPT brass fitting ensemble, as the rearend breather.

The new lower control arms were fastened into place. It's best to do this before installing the springs. Once the install is done and the wheels and tires are back in place, we will use the adjustability of the arms to ensure that the Camaro's rearend is centered, front to back, in the car. We'll do this by measuring the wheels in the their respected wells.

The only problem we had with the install was a little clearance issue with the torque arm within the transmission tunnel. Nothing a small prybar couldn't cure given the soft floorpans.

Nothing was left unscathed after 140,000 miles of driving. Replacing the driveshaft and its undoubtedly worn joints was a no-brainer, and Inland Empire Driveline was our "go-to" supplier. They welded us up this 3-inch aluminum shaft in about a day and a half.

Since the new Moser housing was larger than the stock one, we had to get some new 3-inch sway bar clamps from Hotchkis.

The last piece to put back into place was the Panhard bar. Moser warns that some bars may not clear the beefier Moser Performance rear cover. This wasn't the case with our Hotchkis bar.

We then adjusted the pinion angle. This is done with the car's weight on the suspension. Using a magnetic angle finder, we measured the rearend and driveshaft angle. For complete instructions on the process, download Inland Empire's powertrain setup guide at www.iedls.com/guide.html.

Nan Gelhard of Summit Racing Worlds Speed Shop explains how the company began why enthusiast prefer Summit Racing. Only at www.chevyhiperformance.com, the official website for Chevy High Performance Magazine. » Read More